1. Field of the Invention
The invention relates to a process for preparing a coenzyme Q10/γ-cyclodextrin complex.
2. The Prior Art
Cyclodextrins are cyclic oligosaccharides composed of 6, 7 or 8 α(1-4)-linked anhydroglucose units. The α-, β- or γ-cyclodextrins, which are prepared for example by enzymatic conversion of starch, differ in the diameter of their hydrophobic cavity and are generally suitable for inclusion of numerous lipophilic substances.
Coenzyme Q10 (ubiquinone) is an endocellular component which plays an important part in mitochondrial electron transport. Since it has been known that coenzyme Q10 improves the respiratory chain of the cell and strengthens the mitochondrial membrane, coenzyme Q10 has been employed for treating heart disease. Coenzyme Q10 also acts as free radical scavenger. It is also used for treating degenerative disorders. In addition, coenzyme Q10 improves the release of energy in the body. This property is utilized by the dietary supplement industry in the manufacture of products for sportsmen and for slimming. Coenzyme Q10 is moreover the active component in various cosmetic formulations.
Coenzyme Q10 is a lipid-soluble substance. It is a yellowish powder and is unstable in air. Its solubility in water is very poor. A formulation with γ-cyclodextrin is stable to air and light and increases the solubility in water and the bioavailability.
The complexation of coenzyme Q10 with various cyclodextrins and cyclodextrin derivatives using a kneading and a heating method is described in the Journal Acta Poloniae Pharmaceutica (1995), vol. 52, No. 5, pp. 379-386 and 1996, vol. 53, No. 3, pp. 193-196. The processes described therein for preparing a γ-cyclodextrin complex with coenzyme Q10 show various disadvantages on the production scale.
On use of the kneading method on the production scale, the dispersion necessary for complexation of the coenzyme Q10 is ensured only after agitation of the mixture for several hours. In the heating method, the material is kept at 333 K in a closed vessel for 164 hours. For economic reasons, therefore, these methods cannot be used to prepare a γ-cyclodextrin/coenzyme Q10 complex on the production scale.